[libcxx] By default, do not use internal_linkage to hide symbols from the ABI Summary: https://reviews.llvm.org/D49240 led to symbol size problems in Chromium, and we expect this may be the case in other projects built in debug mode too. Instead, unless users explicitly ask for internal_linkage, we use always_inline like we used to. In the future, when we have a solution that allows us to drop always_inline without falling back on internal_linkage, we can replace always_inline by that. Note that this commit introduces a change in contract for existing libc++ users: by default, libc++ used to guarantee that TUs built with different versions of libc++ could be linked together. With the introduction of the _LIBCPP_HIDE_FROM_ABI_PER_TU macro, the default behavior is that TUs built with different libc++ versions are not guaranteed to link. This is a change in contract but not a change in behavior, since the current implementation still allows linking TUs built with different libc++ versions together. Reviewers: EricWF, mclow.lists, dexonsmith, hans, rnk Subscribers: christof, cfe-commits Differential Revision: https://reviews.llvm.org/D50652 git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@339874 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/CMakeLists.txt b/CMakeLists.txt index c93a1e2..f4c7c93 100644 --- a/CMakeLists.txt +++ b/CMakeLists.txt
@@ -120,6 +120,7 @@ option(LIBCXX_ABI_UNSTABLE "Unstable ABI of libc++." OFF) option(LIBCXX_ABI_FORCE_ITANIUM "Ignore auto-detection and force use of the Itanium ABI.") option(LIBCXX_ABI_FORCE_MICROSOFT "Ignore auto-detection and force use of the Microsoft ABI.") +option(LIBCXX_HIDE_FROM_ABI_PER_TU_BY_DEFAULT "Enable per TU ABI insulation by default. To be used by vendors." OFF) set(LIBCXX_ABI_DEFINES "" CACHE STRING "A semicolon separated list of ABI macros to define in the site config header.") option(LIBCXX_USE_COMPILER_RT "Use compiler-rt instead of libgcc" OFF) @@ -662,6 +663,7 @@ config_define_if(LIBCXX_ABI_UNSTABLE _LIBCPP_ABI_UNSTABLE) config_define_if(LIBCXX_ABI_FORCE_ITANIUM _LIBCPP_ABI_FORCE_ITANIUM) config_define_if(LIBCXX_ABI_FORCE_MICROSOFT _LIBCPP_ABI_FORCE_MICROSOFT) +config_define_if(LIBCXX_HIDE_FROM_ABI_PER_TU_BY_DEFAULT _LIBCPP_HIDE_FROM_ABI_PER_TU_BY_DEFAULT) config_define_if_not(LIBCXX_ENABLE_GLOBAL_FILESYSTEM_NAMESPACE _LIBCPP_HAS_NO_GLOBAL_FILESYSTEM_NAMESPACE) config_define_if_not(LIBCXX_ENABLE_STDIN _LIBCPP_HAS_NO_STDIN)
